The invention relates to a system for mobile telecommunication, comprising a first network arranged for mobile telecommunication—the first mobile network—, connected to a first network arranged for nonmobile telecommunication—the first nonmobile network—, suitable for setting up connections between, on the one hand, terminals whose connections are routed by way of routing means within the first nonmobile network, and, on the other hand, terminals whose connections are routed using registers within the first mobile network or registers within a second network arranged for mobile telecommunication—the second mobile network—, a first register in both mobile networks comprising information relating to mobile terminals having the first or second, as the case may be, mobile network as a home network, and a second register comprising information relating to mobile terminals which, irrespective of their home network, make use of the first or second mobile network, respectively, while, if a terminal having the first mobile network as its home network wants to make use of the second mobile network, the second register of the second mobile network receives a user profile from the first register of the first mobile network, comprising system data relating to the user of said terminal. The above relates to the case in which a terminal having the first mobile network as its home network, wants to make use of the second mobile network. The invention, however, also relates to the inverse situation, namely, that a terminal having the second mobile network as its home network, wants to make use of the first mobile network. In said inverse situation, the second register of the first mobile network receives a user profile from the first register of the second mobile network. It is known that a call to a mobile terminal (“mobile user”) abroad (i.e., outside the range of its home network), is first routed to the home network. Then, it is rerouted from the home network to the destination network, where the user/terminal is located. For the inverse situation, the same applies—mutatis mutandis. All of this implies a long routing path for this kind of call. This results in additional costs (an interconnection twice), a more extensive connection-buildup time and a deteriorated speech quality, since a longer path has to be covered.